This invention relates generally to outdoor sign constructions and, in particular, to a sign construction for outdoor photographic transparencies or other thin-walled rear-illuminated murals.
Large photographic transparencies for indoor use are known in the art. Such photographic transparencies are constructed by splicing large processed strips of film together to form a transparency of the desired size having a unitary oversized picture thereon. One exemplary large indoor color photographic transparency of this type is displayed above the main waiting room of Grand Central Station in New York City. The tranparency forms a large display surface which is illuminated from the rear to provide a beautiful picture.
However, use of a similar sign construction outdoors with a thin-walled transparency has so far proven impractical. Specifically, large transparencies undulate due to wind currents when displayed outdoors. The undulations become stronger and more frequent as wind velocity increases. Eventually, the undulations produced by high winds create stresses in the film and splices, stretch or otherwise deform the transparency and eventually destroy the integrity of the transparency. Supporting structures to prevent film undulation in outdoor installations have to date been impractical, costly and detrimental to the visual impact of a large backlit transparency.
Accordingly, it is desired to provide a sign construction that is practical for outdoor display of large rear-illuminated photographic transparencies or other thin-walled murals.